Top

Research Article

Split Viewer

Mol. Cells 2007; 24(1): 95-104

Published online August 31, 2007

© The Korean Society for Molecular and Cellular Biology

Acacetin-induced Apoptosis of Human Breast Cancer MCF-7 Cells Involves Caspase Cascade, Mitochondria-mediated Death Signaling and SAPK/JNK1/2-c-Jun Activation

Hye-Young Shim, Jong-Hwa Park, Hyun-Dong Paik, Seung-Yeol Nah, Darrick S.H.L. Kim and Ye Sun Han

Abstract

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition (IC50) of MCF-7 cells at 26.4 ? 0.7 ?M over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with 100 ?M acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun NH4-terminal kinase 1/2 (SAPK/ JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.

Keywords Acacetin; Apoptosis Inducing Factor; Bax; Bcl-2; c-Jun; c-Jun NH4-Terminal Kinase; Caspase; Cytochrome c; Mitochondrial Membrane Potential; Reactive Oxygen Species.

Article

Research Article

Mol. Cells 2007; 24(1): 95-104

Published online August 31, 2007

Copyright © The Korean Society for Molecular and Cellular Biology.

Acacetin-induced Apoptosis of Human Breast Cancer MCF-7 Cells Involves Caspase Cascade, Mitochondria-mediated Death Signaling and SAPK/JNK1/2-c-Jun Activation

Hye-Young Shim, Jong-Hwa Park, Hyun-Dong Paik, Seung-Yeol Nah, Darrick S.H.L. Kim and Ye Sun Han

Abstract

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition (IC50) of MCF-7 cells at 26.4 ? 0.7 ?M over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with 100 ?M acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun NH4-terminal kinase 1/2 (SAPK/ JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.

Keywords: Acacetin, Apoptosis Inducing Factor, Bax, Bcl-2, c-Jun, c-Jun NH4-Terminal Kinase, Caspase, Cytochrome c, Mitochondrial Membrane Potential, Reactive Oxygen Species.

Mol. Cells
Aug 31, 2022 Vol.45 No.8, pp. 513~602
COVER PICTURE
Cryo-EM structure of human porphyrin transporter ABCB6 (main figure) shows that binding of hemin (inset, magenta) in concert with two glutathione molecules (cyan) primes ABCB6 for high ATP turnover (Kim et al., pp. 575-587).

Share this article on

  • line
  • mail

Molecules and Cells

eISSN 0219-1032
qr-code Download